I’m attempting to test Accept Hosted payment pages with my sandbox.  For this, I’m using the GetAnAcceptPaymentPage from the C# sample code application to generate a token string for a payment, having first edited the RunMethod function in SampleCode.cs to specify the apuLoginId and transactionKey for my sandbox, and setting $1.00 as the amount. I’m then posting the returned token string to https://test.authorize.net/payment/payment with a “token” form element containing that string.  This much appears to be working, and I do get a payment page showing the $1.00 amount.  However, no matter what values I enter onto that payment page, pressing the “Pay” button just shows “The transaction has been declined.” in red text at the bottom of the form.  I’ve confirmed that my sandbox is set to “Live” mode, and have looked at the following link to use what I believe should be valid values for testing: https://developer.authorize.net/hello_world/testing_guide/.  I'm hoping someone can tell me why I can't get any result other than "The transaction has been declined".

Edit: I tried to include a screenshot showing the form values, but the forum won't accept it, so here are the values as text:

Amount: $1.00

Card #: 5424 0000 0000 0015

Exp date: 08/18

Card code: 900

First name: David

Last name: Tester

Country: USA

ZIP: 46214

Address: 123 Test St

City: Indianapolis

State: IN

Phone: 952-925-9252